umash-sys: rust FFI bindings for UMASH

UMASH is a family of fast hash / fingerprinting functions with collision bounds. This crate builds on x86-64 (with CLMUL) and little-endian aarch64 (with VMULL). The UMASH family of functions is defined independently of hardware specific features, so computes the same values on both architecture.

See https://github.com/backtrace-labs/umash for more details.